The research, published in Science Advances, was led by the Center for Macroecology, Evolution and Climate, University of Copenhagen, Denmark, in partnership with other institutions including King Abdullah University Science & Technology, Saudi Arabia.

It shows that the common cuckoo, red-backed shrike and thrush nightingale find food by following complex seasonal vegetation changes in their non-breeding grounds in sub-Saharan Africa. It also highlights differences between bird species — cuckoos track the newest green vegetation, whereas thrush nightingales and red-backed shrikes stay in areas of seasonal vegetation peaks with a food surplus.

Simulated models for 2080, which are based on Inter-governmental Panel on Climate Change climate change scenarios, show a mismatch between the annual schedule of the migration and available seasonal greenness necessary to sustain the birds. The consequences are potentially severe.

“We don’t know how well birds will adapt,” says Copenhagen’s lead bird migration researcher Kaspar Thorup. “For the shrike and the nightingale, our simulations indicate that even adjusted routes cannot attain the surplus greenness of today. In this case, we expect this to be a contributing factor to declines in these migrants.”